3/4-Hard ASTM F15 Alloy
3/4-hard ASTM F15 is ASTM F15 Fe-Ni-Co in the 3/4-hard temper. It has the second highest strength compared to the other variants of ASTM F15 Fe-Ni-Co. The graph bars on the material properties cards below compare 3/4-hard ASTM F15 to: low-expansion iron alloys (top), all iron alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Elastic (Young's, Tensile) Modulus
190 GPa 28 x 106 psi
Poisson's Ratio
0.3
Shear Modulus
73 GPa 11 x 106 psi
Tensile Strength: Ultimate (UTS)
750 MPa 110 x 103 psi
Thermal Properties
Curie Temperature
430 °C 810 °F
Latent Heat of Fusion
270 J/g
Melting Completion (Liquidus)
1410 °C 2570 °F
Melting Onset (Solidus)
1450 °C 2640 °F
Specific Heat Capacity
460 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
17 W/m-K 9.8 BTU/h-ft-°F
Thermal Expansion
6.0 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
3.7 % IACS
Electrical Conductivity: Equal Weight (Specific)
4.0 % IACS
Otherwise Unclassified Properties
Base Metal Price
49 % relative
Density
8.3 g/cm3 520 lb/ft3
Embodied Carbon
5.2 kg CO2/kg material
Embodied Energy
71 MJ/kg 30 x 103 BTU/lb
Embodied Water
190 L/kg 23 gal/lb
Common Calculations
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
23 points
Strength to Weight: Axial
25 points
Strength to Weight: Bending
22 points
Thermal Diffusivity
4.5 mm2/s
Thermal Shock Resistance
47 points
Alloy Composition
| Fe | 50.3 to 56 | |
| Ni | 28 to 30 | |
| Co | 16 to 18 | |
| Mn | 0 to 0.5 | |
| Si | 0 to 0.2 | |
| Cr | 0 to 0.2 | |
| Mo | 0 to 0.2 | |
| Cu | 0 to 0.2 | |
| Al | 0 to 0.1 | |
| Ti | 0 to 0.1 | |
| Zr | 0 to 0.1 | |
| Mg | 0 to 0.1 | |
| C | 0 to 0.040 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Further Reading
ASTM F15: Standard Specification for Iron-Nickel-Cobalt Sealing Alloy
Properties and Selection: Irons, Steels and High Performance Alloys, ASM Handbook vol. 1, ASM International, 1993
Manufacture and Uses of Alloy Steels, Henry D. Hibbard, 2005